Deleptonizes

Deleptonizes is a term used in physics to describe the act of removing leptons from a system, or reducing its lepton content. In astrophysics, it commonly refers to the loss of electron lepton number from dense stellar matter due to emission or escape of neutrinos, particularly electron neutrinos. The related noun deleptonization denotes the overall reduction of the lepton fraction in a region of matter.

In core-collapse supernovae and the early evolution of proto-neutron stars, deleptonization proceeds as electron neutrinos diffuse out of the hot core. Electron captures (p + e- → n + ν_e) generate ν_e; when these neutrinos escape, they remove lepton number, lowering the electron fraction Ye and the total lepton fraction Y_L on timescales of seconds to tens of seconds after core bounce, thereby influencing the equation of state and the dynamics of the explosion.

Significance: The deleptonization history shapes the neutrino signal and the synthesis of elements in neutrino-driven winds; observations of supernova neutrinos provide tests of theoretical models. In cooling neutron stars, continued neutrino emission drives further deleptonization and cooling, leaving a cold, lepton-poor remnant.

Relation to other terms: Deleptonization is related to neutronization, the proton-to-neutron conversion process driven by electron capture, but broader in scope as it includes the loss of leptons via neutrinos.

See also: Lepton number, Electron capture, Neutrino diffusion, Proto-neutron star, Core-collapse supernova.